The classical definition of knowledge is that it is a true justified belief. In other words, knowledge is a state of mind that is about the world, that it is true and such that good reasons can be given for the content of the belief. One may say that the concept of knowledge connects the subjective, the intersubjective and the objective aspect of a state of mind.
We accept in all empirical sciences, in everyday life and in the courts that a piece of evidence could be very good reason for a belief without providing a complete guarantee for truth. Hence, since there is no strict connection between good reason and truth, it may happen that we have very good reason for a false belief. And further, Gettier discovered that we may have good reasons for a true belief, but we still do not want to say that that belief constitutes knowledge; we believe the proposition for the wrong reason, it seems. This has inspired many philosophers to suggest an alternative definition of knowledge, viz. that it is a true belief, which is arrived at by a reliable procedure. The point is that the person who is attributed a piece of knowledge may not know that he/she in fact used a reliable process. The reasons he/she may give for the belief is not relevant.
So what is knowledge? Philosophers disagree; but they do not disagree about the truth-condition; a false belief cannot be knowledge.
Discussion Exercises
1. Detective Carl Blomkvist is investigating a murder. At the scene of the crime he finds a wallet containing a driver’s license that belongs to a Pelle Persson. The detective seeks him out and discovers that Pelle Persson left town in a hurry. It just so happens that Pelle Persson has long been in conflict with the victim and had much to gain from the victim’s death. Pelle Persson is arrested; under his
fingernails the police find traces of the victim’s blood. The police also find a large number of fingerprints belonging to Pelle Persson at the scene of the crime.
There are no other suspects; and so Carl Blomkvist becomes convinced that Pelle Persson is the murderer.
In fact, Pelle Persson is not the murderer. Another person is, and he has succeeded in simultaneously hiding his involvement and framing Pelle Persson.
Does Carl Blomkvist know that Pelle Persson is the murderer?
2. In the 1500s, the geocentric worldview was still the established view. Among other things, this worldview enabled seafarers to determine their latitude when sailing on the open ocean by reference to the positions of the sun and other celestial bodies. Even though their worldview was not correct, their latitudinal calculations were.
When such a seafarer correctly believes that his latitude is x degrees on the basis of the instruments and techniques of the day, does he know it?
3. Lady G is on a walk in the inner city of London and is thinking about classic rock’n roll. She sees a man on a street corner that she has seen on TV many times, as well as in the newspapers. However, he looks a bit older than he did in the pictures she saw. She stares intently at the person and says to herself,‘My God, that is Elvis Presley! I saw him!’
In actuality, what Lady G tells herself is true. Elvis Presley is in fact living a quiet life in London, and it was just this person that she has met. However, at the time of this occurrence there is an Elvis Presley look-alike competition going on in London, so the city is crawling with Elvis impersonators. This event is well known and all over the tabloids, but Lady G does not read those papers and has no idea that the competition is taking place.
Does Lady G know that she saw Elvis Presley?
4. Doctor H prescribes medicine M to a patient P. This medicine has been carefully tested and has been used for 20 years with a 100 % success rate, and no side effects. Doctor H knows all of this when she writes out the prescription; she claims that it will cure the patient and it does. However, no one knows how medicine M works. It is a complete mystery.
Does Doctor H know that the patient will be cured?
5. Discuss the following propositions! Do you agree?
(a) A proposition can be true even though everyone thinks that it is false.
(b) A proposition can be true even though no one can give reasons for believing it.
(c) A proposition can be false even though one has good reasons for believing it is true.
(d) If one has good reasons for believing a proposition, then one knows it.
(e) If everyone considers a proposition to be true, then it is true.
(f) Many propositions that were true 500 years ago are now false.
(g) If one knows that a proposition is true, then it is true.
(h) If one knows that a proposition is true, then one believes it is true.
(i) If one believes that a proposition is true, then one knows that it is true.
2.10 Summary 39
(j) 500 years ago, everyone knew that the earth was the centre of the universe, but now we know that the earth is not the centre of the universe.
(k) There is nothing that we know for certain.
Further Reading
Floridi, L. (2011).The philosophy of information. Oxford: Oxford University Press.
Hospers, J. (1986).Introduction to philosophical analysis. London: Routledge.
Kornblith, H. (2002).Knowledge and its place in nature. Oxford: Clarendon.
Longino, H. E. (2002).The fate of knowledge. Princeton: Princeton University Press.
Plato. (ca. 400 BC).Theatetus.http://www.gutenberg.org/ebooks/1726
Williams, M. (2001).Problems of knowledge. A critical introduction to epistemology. Oxford:
Oxford University Press.
Wiseman, R. (2011).Paranormality. London, Basingstoke and Oxford: MacMillan.
Chapter 3
Hypotheses and Hypothesis Testing
We and other animals notice what goes on around us. This helps us by suggesting what we might expect and event how to prevent it, and thus fosters survival. However, the expedient works only imperfectly. There are surprises, and they are unsettling. How can we tell when we are right? We are faced with the problem of error.
W. V. O. Quine